William w



(No Model.)

W. W. GRISGOM.

DYNAMO ELECTRIC MACHINE.

No. 898,469. Patented Nov. 27, 1888.

f ui mu' I 4 I UNITED STATES PATENT rEIcE.

\VILLIAM WV. GRISOOM, OF HAVERFORD COLLEGE, PENNSYLVANIA, ASSIGNOR TO THE ELEOTIi-O DYNAMIC COMPANY OF PHILADELPHIA.

DYNAMO-ELECTRlC MACE-NINE.

SPECIFICATION forming part of Letters Patent No. 393,;69, dated November 27, 1888.

Application filed June 30, 1588. Serial NmQTSfiiwl. (Nomodela T to whom it may concern:

Beit known that I, WILLIAM W. GRIscoM, a citizen of the United States, and a resident of Haverford College, in the county of Montgomery and State of Pennsylvania, have invented certain new and useful Improvements in Dynamo-Electric Machines, of which the following is a specification.

My invention is an improvement in details of construction of dynamo-electric machines or motors.

The improvements specially concern the construction of the armature.

I form my'armature-core from a series of 1 convolutions of soft-iron wire wound upon a frame work. This frame-work itself I also construct ofsoftiron. The use of such wire avoids the circulation of magnetic variations or magnetic eddies. By using a frame-work of magneticmaterial-as ironI add to the magnetic volume and provide a framework of considerable strength without the addition of much weight. If clean iron strips were used, the several successive convolutions of the wire would be magnetically unitedthat is, the benefits due to the use of the wire would be neutralized by connecting one convolution with another in such a manner that magnetic currents, eddies, or variations could circulate in the entire mass of iron as a whole; but by covering the surface of this framework with a non-magnetic metal such connection is avoided and each convolution, as well as the frame-work, is magnetically independent. I have found tinned iron to answer this purpose exceedingly well, and I therefore construct the framework of my armature of tinned iron. By placing in position a framework of tinned iron and winding one or more layers of the iron wire thereon, then placing in position a second series of tinned-iron strips and winding more iron wire thereon, Iain enabled to produce a firmer and a more mechanically perfect armature-core.

The accompanying drawings illustrate my invention.

Figure 1 is an end view. Fig. 2 is a longitudinal section. Fig. 3 is a detail.

R indicates a ring of cast-iron, having a cross-section, as shown in Fig. 2.

Sis a spider, preferably of brass, having four or more arms or projections entering notchesfin the iron rings R, and serving to support the rings, and to thus equalize and distribute the points of support of the weight of the armature. These spiders are keyed to a shaft, 8, in the usual manner. At intervals I fixaseries of strips of tinned iron, u, to corresponding peripheral points of the two rings, each and every strip of this series being at the same radial distance from the center, and I rivet these strips a to the shoulder of the ring R, as at r. Each strip of this series is sepa rated from the one next succeeding by an equal circumferential distance. A second series of tinned-iron strips, m, are placed at equal circumferential distances, each and every strip being located at an equal radial distance at points between the first-named series of strips and the center, but in every case in the same radial line. On both sides of both series of strips, and also between these tinned-iron strips, I place soft-iron wire of comparatively large gage, which I prefer to wind on in the direction of rotation. By this means magnetic eddy-currents are almost entirely avoided. 7 The armature is aired and retained at a low temperature under the effects of continued use, and the weight of the structure is equally dis tributed, while for its generative power the armature is extremely light.

The copper conducting-wire is wound and connected to cornmutator-segments after what is generally called the Gramme plan, and the field-magnets are of any well-known construction.

WVhat I claim, and desire to secure by Letters Patent, is

1. The combination, in a dynamo-elcctrie machine, of an armature composed of two parallel cast-iron rings, strips of tinned iron uniting said rings at equidistant circumferential points, and one or more layers of soft-iron wire enveloping said strips in non-magnetic contact therewith.

2. The combination, in a dynamo-electric machine, of an armature composed of two parallel cast-iron rings, two concentric series of tinned-iron strips, having their opposite ends connected to said rings, respectively, and one or more layers of softiron wire enveloping said strips in non-magnetic contact therewith.

3. In a dynamo-armature, the combination of two parallel cast-iron rings respectively Signed at New York, in the county of New connected to a rotating shaft by spiders of non- York and State of New York, t is 28th day of magnetic material, a series of binned-iron June, A. D. 1888.

strips connecting the two rings, and one or \V. W. GRISOOM. 5 more layers of soft-iron wire uniformly dis- Vibnesses:

posed upon or around the said strips, substan- DANIEL E. DELAVAN,

tially as described. WM. B. VANsIzEQ 

